I think there will be a “Big incident” caused by the Straw Hat Grand Fleet, and it is the set up for the Luffy-Shanks meet up. This has obviously been discussed before but it got way more likely after Chapter 1054 and 1055.
First, it would be pretty disappointing if their meeting happened with Shanks just strolling by after Luffy accomplishes something and him going “hey man, great work, you are a great pirate now”. Oda had the opportunity for this in Wano and Marineford and it’s pretty clear he isn’t going that way.
Second, while Shanks was the one who taught Luffy the freedom of the pirate life, he was also the first one to teach him the harsh responsibilities pirates have since Chapter 1.
Considering this and what we saw in chapter 1054, it’s pretty clear that he isn’t gonna led Barto actions slide. He caused ruckus in a place protected by him and disrespected his crew’s accomplishments.
That said, I think their meet up will happen in context that Shanks will deal with Barto and other commanders and Luffy will be called into helping them. The “Big incident caused by the Straw Hat Grand Fleet” hinted by the narrator in Chapter 800 is the confrontation between these 2 Yonkou.
Nonetheless, I don’t think this is gonna be a whole arc and after Luffy gathers his resolve to really confront Shanks, he will call it a truce and recognize Luffy as a great pirate that is willing to defend his companions.
TL;DR: The big incident hinted at Chapter 800 is the Straw Hat Grand Fleet causing a confrontation between Luffy and Shanks and will be the set up for their meeting.
Theory by great_thunder01 (https://www.reddit.com/user/great_thunder01)